Chronic Nicotine Exposure Increases Hematoma Expansion following Collagenase-Induced Intracerebral Hemorrhage in Rats

Multiple intracerebral hematomas during SEEG recording and intradural hemorrhage after spinal tap: A case report prompting more research on collagen IV gene mutation and oral nicotine consumption as risk factors

Intracerebral hemorrhages (ICH) during implantation of stereo-EEG electrodes are rare. The impact of tobacco-free nicotine consumption on periprocedural bleeding is uncertain. We present a 20+ year-old man with drug-resistant epilepsy who underwent stereo-EEG with 17 depth electrodes. Within a few days after insertion, the patient developed multiple ICHs in the electrode trajectories and an intradural hemorrhage after a diagnostic spinal tap. We performed the investigation of the clotting system and whole-exome sequencing (WES). WES identified a heterozygous mutation c.4698G>T, p.(Trp1566Cys) in COL4A2 (NM_001846.4) encoding a collagen type-IV alpha-2 chain inherited from his seemingly healthy mother. As COL4A2 mutations had been identified in four adult patients with ICH we postulated that the identified variant presents a potential risk factor. Notably, mutations encoding other collagens have been linked to cerebral hemorrhages (COL4A1) and increased propensity to trigger ICH upon smoking (COL1A2). Our patient consumed at least 24 oral nicotine pouches (containing 11 mg nicotine each) per day. We consider the patient's COL4A2 mutation in combination with his substantial nicotine consumption as likely predisposition to multiple ICHs precipitated by stereo-EEG. Patients with nicotine consumption and any collagen mutation may have a substantially higher risk for hemorrhagic complications in SEEG and other neurosurgical procedures. PLAIN LANGUAGE SUMMARY: A young man with drug-resistant epilepsy experienced multiple intracerebral hemorrhages after implantation of SEEG electrodes for presurgical evaluation and concomitantly a intradural hemorrhage after a lumbar spinal tap. A collagen IV mutation of unclear significance and heavy use of oral nicotine pouches were the only potential risk factors identified. As collagen mutations were previously described risk factors and smoking in particular worsens the bleeding risk in collagen mutations, further research is warranted to prevent hemorrhages in neurosurgical procedures. Nicotine consumption in any form is a preventable risk factor.

NU7441, a selective inhibitor of DNA-PKcs, alleviates intracerebral hemorrhage injury with suppression of ferroptosis in brain

Neuronal apoptosis, oxidative stress, and ferroptosis play a crucial role in the progression of secondary brain injury following intracerebral hemorrhage (ICH). Although studies have highlighted the important functions of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in various experimental models, its precise role and mechanism in ICH remain unclear. In this study, we investigated the effects of DNA-PKcs on N2A cells under a hemin-induced hemorrhagic state in vitro and a rat model of collagenase-induced ICH in vivo. The results revealed a notable increase in DNA-PKcs levels during the acute phase of ICH. As anticipated, DNA-PKcs and γ-H2AX had consistent upregulations after ICH. Administration of NU7441, a selective inhibitor of DNA-PKcs, alleviated neurological impairment, histological damage, and ipsilateral brain edema in vivo. Mechanistically, NU7441 attenuated neuronal apoptosis both in vivo and in vitro, alleviated oxidative stress by decreasing ROS levels, and suppressed ferroptosis by enhancing GPX4 activity. These results suggest that inhibition of DNA-PKcs is a promising therapeutic target for ICH.

Cigarette Smoking as a Risk Factor for Hematoma Expansion in Primary Intracerebral Hemorrhage: Analysis From a Randomized Clinical Trial

Background Cigarette smoking is a well-known risk factor for ischemic and hemorrhagic stroke. We evaluated the impact of smoking status on hematoma expansion and clinical outcome in patients with primary intracerebral hemorrhage. Methods and Results This is a post hoc exploratory analysis of the ATACH (Antihypertensive Treatment at Acute Cerebral Hemorrhage)-2 trial. Patients with intracerebral hemorrhage were randomized into intensive blood pressure lowering (systolic blood pressure, <139 mm Hg) versus standard blood pressure lowering (systolic blood pressure, 140-179 mm Hg) in this study. We compared the demographic characteristics; hematoma size, location, and expansion rate; and clinical outcome based on subjects' smoking status. Of a total of 914 patients in the trial with known smoking status, 439 (48%) patients were ever smokers (264 current smokers and 175 former smokers). Current and former smokers were younger and more likely to be men. Baseline Glasgow Coma Scale score and initial hematoma size did not vary based on smoking status. Ever smokers had higher rates of thalamic hemorrhage (42% versus 34%) and intraventricular hemorrhage (29% versus 23%); this rate was highest among former smokers versus current smokers (49% versus 35%, respectively). Ever smokers had a higher rate of hematoma expansion in 24 hours (adjusted relative risk [RR] [95% CI], 1.46 [1.08-1.96]) compared with nonsmokers on multivariate analysis. There was no significant difference in the rate of death and disability at 90 days between the 2 groups (adjusted RR [95% CI], 1.18 [0.998-1.40]). Conclusions Our analysis demonstrates cigarette smoking as an independent predictor for hematoma expansion. There was no significant difference in death and disability based on smoking status.

Red Cell Microparticles Suppress Hematoma Growth Following Intracerebral Hemorrhage in Chronic Nicotine-Exposed Rats

Spontaneous intracerebral hemorrhage (sICH) is a disabling stroke sub-type, and tobacco use is a prominent risk factor for sICH. We showed that chronic nicotine exposure enhances bleeding post-sICH. Reduction of hematoma growth is a promising effective therapy for sICH in smoking subjects. Red-blood-cell-derived microparticles (RMPs) are hemostatic agents that limit hematoma expansion following sICH in naïve rats. Considering the importance of testing the efficacy of experimental drugs in animal models with a risk factor for a disease, we tested RMP efficacy and the therapeutic time window in limiting hematoma growth post-sICH in rats exposed to nicotine. Young rats were chronically treated with nicotine using osmotic pumps. sICH was induced in rats using an injection of collagenase in the right striatum. Vehicle/RMPs were administered intravenously. Hematoma volume and neurological impairment were quantified ≈24 h after sICH. Hematoma volumes in male and female nicotine-exposed rats that were treated with RMPs at 2 h post-sICH were significantly lower by 26 and 31% when compared to their respective control groups. RMP therapy was able to limit hematoma volume when administered up to 4.5 h post-sICH in animals of both sexes. Therefore, RMPs may limit hematoma growth in sICH patients exposed to tobacco use.